A comparison of carbon removal solutions
KATY: Scaling any kind of new technology can be challenging, and DAC is not the only solution in the carbon removal space. How does DAC compare to those other technologies, including in terms of cost competitiveness, now and in the future?
CHRISTOPH: To reach net zero, several billion tonnes of carbon would need to removed from the atmosphere by 2050, every year. That represents a multi-trillion market opportunity. We are talking about something very substantial which is still in its infancy today.
How are we going to get to this amount of carbon removal? One-third of it will have to come from nature-based solutions, mainly afforestation projects which involve planting forests in areas with no previous tree cover. Fortunately, these solutions already exist at scale today, and are low in cost. However, they also have an inverted cost curve and will become more expensive over time because of their reliance on arable land which is an increasingly scarce resource.
Ensuring that these projects are implemented in a thoughtful way is an additional challenge. For example, cutting down and reforesting original forests which were previously home to a diversity of animal and plant species with monocultures, especially if done at a very large scale, could have unintended consequences for local ecosystems.
The second pillar is hybrid solutions which combine nature and technology such as the UK company Drax, which aims to generate carbon negative electricity using bioenergy with carbon capture and storage (BECCS). These solutions still have an extensive land impact but can store CO2 for a very long time.
Pure technology-based approaches should account for the removal of the remainder CO2, which is what we focus on. These solutions would not require arable land and could be virtually implemented anywhere in the world, including in areas with little to no vegetation. They also make a clear case for additionality, meaning that the emission reductions achieved would not have happened unless the project was implemented, which does not always apply to nature-based solutions.
Scalability is a given since it’s a tech solution, but it’s also currently the most expensive approach at $800 to $900/tonne. Based on other successful, modular climate technologies, we are, however, expecting a rather steep reduction in costs, landing somewhere between $100 to $150/tonne in the next 10 years.